Currently the most prevalent instance of refillable storage devices are flash drives, also commonly referred to as universal serial bus (USB) thumb drives. Other similar USB-connected, solid state memory-based, mass storage devices are in common usage.
Today, flash drives are readily available in multi-gigabyte (GB) capacities. This opens the possibility of using these devices to store and transport very large files such as full length, high-definition movies. Using a modern video coding scheme such as motion picture experts group (MPEG) version 4.10, a 2 hour high definition (e.g., a 720 line progressive scan (720 P)) movie would require approximately 6 GB of storage. Even though flash drives now have very large capacities, the time it takes to transfer a 6 GB file is quite long. Typical write speeds for devices today range from 5 megabytes per second (MB/sec) to 20 MB/sec, with most closer to 5 MB/sec. Thus it could take up to 20 minutes to transfer a single high definition movie file to a typical flash drive.